Operations Research, Systems Engineering and Industrial Engineering Commons^™

Relationship Of Surface Changes To Metal Leaching From Tungsten Composite Shot Exposed To Three Different Soil Types, Deborah Felt, Steven Larson, Chris Griggs, Catherine Nestler, Michelle Wynter

US Army Research

Physical changes that occur on the surface of fired shots due to firing and impact with soil may increase the dissolution of muniton metals. Increased metal dissolution could potentially increase metal transport and leaching, affecting metal concentrations in surface and groundwater. This research describes the relationship between the surface changes on fired tungsten–nickel–iron (94% W:2% Ni:4% Fe) composite shots and metals leaching from those shots. Tungsten composite shot was fired into, and aged in, three soil types (Silty Sand, Sandy Clay, and Silt) in mesoscale rainfall lysimeters to simulate live-fire conditions and subsequent interactions between the metals of the composite …

Determination Of Threshold Adverse Effect Doses Of Percutaneous Vx Exposure In African Green Monkeys, Raymond F. Genovese, Bernard J. Benton, John L. Oubre, Christopher E. Byers, E. Michael Jakubowski, Robert J. Mioduszewski, Timothy J. Settle, Thomas J. Steinbach

US Army Research

Percutaneous exposure to the chemical warfare nerve agent VX was evaluated in African green monkeys (n = 9). Doses of VX (7.5–100 μg/kg) were applied to the skin for 60 min and residual agent was quantified (before decontamination) to estimate the absorbed dose. Monkeys were evaluated for the presence or absence of clinical signs of toxicity and blood was sampled periodically (30 min–12 weeks) following exposure to measure the degree of circulating acetylcholinesterase (AChE) inhibition. Monkeys were also evaluated for behavioral changes fromVXexposure using a serial probe recognition (SPR) task. The lowest observable adverse effect level (LOAEL) for the production …

Investigations Of Transcript Expression In Fathead Minnow (Pimephales Promelas) Brain Tissue Reveal Toxicological Impacts Of Rdx Exposure, Kurt A. Gust, Mitchell S. Wilbanks, Xin Guan, Mehdi Pirooznia, Tanwir Habib, Leslie Yoo, Henri Wintz, Chris D. Vulpe, Edward J. Perkins

US Army Research

Production, usage and disposal of the munitions constituent (MC) cyclotrimethylenetrinitramine (RDX) has led to environmental releases on military facilities. The chemical attributes of RDX are conducive for leaching to surface water which may put aquatic organisms at risk of exposure. Because RDX has been observed to cause aberrant neuromuscular effects across a wide range of animal phyla, we assessed the effects of RDX on central nervous system (CNS) functions in the representative aquatic ecotoxicological model species, fathead minnow (Pimephales promelas). We developed a fathead minnow brain-tissue cDNA library enriched for transcripts differentially expressed in response to RDX and …

Nanoindentation Characterization Of Deformation And Failure Of Aluminum Oxynitride, J. J. Guo, K. Wang, T. Fujita, J. W. Mccauley, J. P. Singh, M. W. Chen

US Army Research

A systematic study of the mechanical deformation and failure of transparent ceramic aluminum oxynitride (AlON) has been conducted using a depth-sensitive nanoindentation technique combined with transmission electron microscopy (TEM) and Raman spectroscopy. Although discrete displacement bursts appear in the load–depth profiles at high applied forces, a detectable high-pressure phase transition has not been found by means of micro-Raman spectroscopy and TEM. Instead, a high density of dissociated (1 1 0) dislocations can be observed underneath the nanoindenters, suggesting that extensive plastic deformation takes place in the brittle ceramic at high contact pressures. Moreover, nanoindentation-induced micro-cracks oriented along well-defined crystallographic planes …

Eating Rate During A Fixed-Portion Meal Does Not Affect Postprandial Appetite And Gut Peptides Or Energy Intake During A Subsequent Meal, J. Phillip Karl, Andrew J. Young, Scott J. Montain

US Army Research

Eating rate has recently been shown to influence energy intake and appetite during an ad libitummeal, and alter postprandial secretion of glucagon-like peptide-1 (GLP-1) and peptide-YY (PYY) following a fixed-portionmeal. Whether these effects influence satiety, as measured by energy intake at the subsequent meal, is unclear. We manipulated eating rate during a fixed-portion meal in order to examine how eating behavior and associated periprandial and postprandial responses of putative endocrine mediators of appetite would affect energy intake at the following meal in fifteen non-obese (BMI ≥ 25 kg/m²) and ten obese (BMI ≥ 30 kg/m²) healthy adult men and …

Fatigue-Induced Grain Coarsening In Nanocrystalline Platinum Films, Roi A. Meirom, Daan Hein Alsem, Amber L. Romasco, Trevor Clark, Ronald G. Polcawich, Jeffrey S. Pulskamp, Madan Dubey, Robert O. Ritchie, Christopher L. Muhlstein

US Army Research

Mechanisms to explain the unique mechanical behavior of nanograined metals focus primarily on grain and grain boundary mobility. In most nanograined metal materials systems (both pure and alloyed) it has not been possible to decouple these time- and cycle-dependent contributions. In contrast, the 460 nm thick, (1 1 1) textured, nanograined platinum thin films evaluated in this work have robust grain morphologies that allow us to uniquely identify the fatigue damage accumulation processes. Unlike other reports of face-centered cubic metal behavior, the platinum films exhibited a particularly limited range of fatigue crack growth (<3 MPa √m) with extremely large (~10.5) power law exponents typically associated with fatigue of structural ceramics and ordered intermetallics. Transmission electron microscopy and fatigue crack growth data suggest that the crack growth mechanism appears to be intrinsic in origin and dislocation mediated.

Effects Of Gage Length, Loading Rates, And Damage On The Strength Of Ppta Fibers, Jaeyoung Lim, James Q. Zheng, Karl Masters, Weinong W. Chen

US Army Research

Axial tension and transverse compression experiments on single fibers were performed to investigate the mechanical behavior of three high-performance fibers (Kevlar ®, Kevlar ® 129, and Twaron ®) with diameters in the order of 9-12 μm. The single fibers were manufactured from 1998 through 2008. A miniaturized tensile Kolsky bar was used to determine the tensile response of PPTA single fibers at a high strain rate. Gage length and strain rate were found to have minimum effects on the tensile strength of PPTA single fibers. Manufacturing time over a decade was found to have negligible effects on the tensile strength …

Thermoreversible And Remendable Glass–Polymer Interface For Fiber-Reinforced Composites, Amy M. Peterson, Robert E. Jensen, Giuseppe R. Palmese

US Army Research

Adhesion of the reinforcement to the polymer matrix is essential for load transfer from the polymer matrix to the reinforcement material in fiber-reinforced composites. The reversible Diels–Alder reaction between a furan-functionalized epoxy-amine thermosetting matrix with a maleimide-functionalized glass fiber was used to impart remendability at the polymer–glass interface for potential application in glass fiber-reinforced composites. At room temperature the Diels–Alder adduct is formed spontaneously and above 90 °C the adduct breaks apart to reform the original furan and maleimide moieties. Healing of the interface was investigated with single fiber microdroplet pull-out testing. Following complete failure of this interface, significant healing …

Micro-Cracks Informed Damage Models For Brittle Solids, Xiaodan Ren, Jiun-Shyan Chen, Jie Li, T. R. Slawson, M. J. Roth

US Army Research

A class of micro-cracks informed damage models for describing the softening behavior of brittle solids is proposed, in which damage evolution is treated as a consequence of micro-crack propagation. The homogenized stress–strain relation in the cracked microscopic cell defines the degradation tensor, which can be obtained by the equivalence between the averaged strain energy of the microscopic cell and the strain energy density of the homogenized material. This energy equivalence relationship serves as an energy bridging vehicle between the damaged continuum and the cracked microstructure. Several damage evolution equations are obtained by this energy bridging method. The size effect of …

Prophylaxis With Human Serum Butyrylcholinesterase Protects Guinea Pigs Exposed To Multiple Lethal Doses Of Soman Or Vx, Ashima Saxena, Wei Sun, James M. Fedorko, Irwin Koplovitz, Bhupendra P. Doctor

US Army Research

Human serum butyrylcholinesterase (Hu BChE) is currently under advanced development as a bioscavenger for the prophylaxis of organophosphorus (OP) nerve agent toxicity in humans. It is estimated that a dose of 200 mg will be required to protect a human against 2 × LD₅₀ of soman. To provide data for initiating an investigational new drug application for the use of this enzyme as a bioscavenger in humans, we purified enzyme from Cohn fraction IV-4 paste and initiated safety and efficacy evaluations in mice, guinea pigs, and non-human primates. In mice, we demonstrated that a single dose of enzyme that …

Antimicrobial Decapeptide Ksl-W Attenuates Candida Albicans Virulence By Modulating Its Effects On Toll-Like Receptor, Human Β-Defensin, And Cytokine Expression By Engineered Human Oral Mucosa, A. Semlali, K. P. Leung, S. Curt, M. Rouabhia

US Army Research

We investigated the toxicity of synthetic antimicrobial decapeptide KSL-W on normal human gingival epithelial cell cultures, its effect on Candida albicans adhesion and growth, and the activation of epithelial cell innate immunity. Our results indicate that KSL-W had no toxic effect on cell adhesion or growth, suggesting its safe use with human cells. Pre-treating C. albicans with KSL-W attenuated the yeast’s virulence as demonstrated by its reduced adhesion and growth on engineered human oral mucosa epithelium and the subsequent decreased expression of some innate defense molecules by targeted epithelial cells. Indeed, the expression of Toll-like receptors and human β-defensins was …

Safety And Protective Efficacy Of Ina-Inactivated Venezuelan Equine Encephalitis Virus: Implication In Vaccine Development, Anuj Sharma, Paridhi Gupta, Pamela J. Glass, Michael D. Parker, Radha K. Maheshwari

US Army Research

We have previously shown that a hydrophobic alkylating compound, 1,5-iodonaphthyl-azide (INA) can efficiently inactivate the virulent strain of Venezuelan equine encephalitis virus (VEEV), V3000 in vitro. In this study, we have evaluated the safety of INA-inactivated V3000 and V3526 and the protective efficacy of INA-inactivated V3000. INA-inactivated V3000 and V3526 did not cause disease in suckling mice. RNA isolated from the INA-inactivated V3000 and V3526 was also not infectious. Immunization of adult mice with INA-inactivated V3000 induced an anti-VEEV antibody response and protected mice from virulent VEEV challenge. The protective efficacy of INA-inactivated V3000 increased with the use of adjuvants. …

Protective Efficacy Of Catalytic Bioscavenger, Paraoxonase 1 Against Sarin And Soman Exposure In Guinea Pigs, Manojkumar Valiyaveettil, Yonas Alamneh, Peter Rezk, Lionel Biggemann, Michael W. Perkins, Alfred M. Sciuto, Bhupendra P. Doctor, Madhusoodana P. Nambiar

US Army Research

Human paraoxonase 1 (PON1) has been portrayed as a catalytic bioscavenger which can hydrolyze large amounts of chemical warfare nerve agents (CWNAs) and organophosphate (OP) pesticides compared to the stoichiometric bioscavengers such as butyrylcholinesterase. We evaluated the protective efficacy of purified human and rabbit serum PON1 against nerve agents sarin and soman in guinea pigs. Catalytically active PON1 purified from human and rabbit serum was intravenously injected to guinea pigs, which were 30 min later exposed to 1.2 × LCt₅₀ sarin or soman using a microinstillation inhalation exposure technology. Pre-treatment with 5 units of purified human and rabbit serum …

Dislocation–Twin Interactions In Nanocrystalline Fcc Metals, Y. T. Zhu, X. L. Wu, X. Z. Liao, J. Narayan, L. J. Keckés, S. N. Mathaudhu

US Army Research

Dislocation interaction with and accumulation at twin boundaries have been reported to significantly improve the strength and ductility of nanostructured face-centered cubic (fcc) metals and alloys. Here we systematically describe plausible dislocation interactions at twin boundaries. Depending on the characteristics of the dislocations and the driving stress, possible dislocation reactions at twin boundaries include cross-slip into the twinning plane to cause twin growth or de-twinning, formation of a sessile stair-rod dislocation at the twin boundary, and transmission across the twin boundary. The energy barriers for these dislocation reactions are described and compared.

Microstructure And Mechanical Properties At Different Length Scales And Strain Rates Of Nanocrystalline Tantalum Produced By High-Pressure Torsion, Q. Wei, Z. L. Pan, X. L. Wu, B. E. Schuster, L. J. Kecdkes, R. Z. Valiev

US Army Research

Fully dense, nanocrystalline tantalum (average grain size as small as ~40 nm) has been processed for the first time by high-pressure torsion. High-resolution transmission electron microscopy reveals non-equilibrium grain boundaries and grains decorated with high-density dislocations. Microhardness measurements and instrumented nanoindentation experiments indicate that the mechanical property is quite uniform except for the central area of the disks. Nanoindentation experiments at different strain rates suggest that the strain rate sensitivity of nanocrystalline tantalum is increased compared to the coarse- and ultrafine-grained counterparts and is accompanied by an activation energy of the order of a few ~b3 (b is the magnitude …

Recombinant Paraoxonase 1 Protects Against Sarin And Soman Toxicity Following Microinstillation Inhalation Exposure In Guinea Pigs, Manojkumar Valiyaveettil, Yonas Alamneh, Peter Rezk, Michael W. Perkins, Alfred M. Sciuto, Bhupendra P. Doctor, Madhusoodana P. Nambiar

US Army Research

To explore the efficacy of paraoxonase 1 (PON1) as a catalytic bioscavenger, we evaluated human recombinant PON1 (rePON1) expressed in Trichoplusia ni larvae against sarin and soman toxicity using microinstillation inhalation exposure in guinea pigs. Animals were pretreated intravenously with catalytically active rePON1, followed by exposure to 1.2 X LCt₅₀ sarin or soman. Administration of 5 units of rePON1 showed mild increase in the blood activity of the enzyme after 30 min, but protected the animals with a significant increase in survival rate along with minimal signs of nerve agent toxicity. Recombinant PON1 pretreated animals exposed to sarin or …

The Utility Of Shewanella Japonica For Microbial Fuel Cells, Justin C. Biffinger, Lisa A. Fitzgerald, Ricky Ray, Brenda J. Little, Stephen E. Lizewski, Emily R. Petersen, Bradley R. Ringeisen, Wesley C. Sanders, Paul E. Sheehan, Jeremy J. Pietron, Jeffrey W. Baldwin, Lloyd J. Nadeau, Glenn R. Johnson, Meghann Ribbens, Steven E. Finkel, Kenneth H. Nealson

U.S. Navy Research

Shewanella-containing microbial fuel cells (MFCs) typically use the fresh water wild-type strain Shewanella oneidensis MR-1 due to its metabolic diversity and facultative oxidant tolerance. However, S. oneidensis MR-1 is not capable of metabolizing polysaccharides for extracellular electron transfer. The applicability of Shewanella japonica (an agar-lytic Shewanella strain) for power applications was analyzed using a diverse array of carbon sources for current generation from MFCs, cellular physiological responses at an electrode surface, biofilm formation, and the presence of soluble extracellular mediators for electron transfer to carbon electrodes. Critically, air-exposed S. japonica utilizes biosynthesized extracellular mediators for electron transfer to carbon …

Derivation Radical Subspace Arrangements, Will Taves, Max Wakefield

U.S. Navy Research

In this note we study modules of derivations on collections of linear subspaces in a finite dimensional vector space. The central aim is to generalize the notion of freeness from hyperplane arrangements to subspace arrangements. We call this generalization ‘derivation radical’. We classify all coordinate subspace arrangements that are derivation radical and show that certain subspace arrangements of the Braid arrangement are derivation radical. We conclude by proving that under an algebraic condition the subspace arrangement consisting of all codimension c intersections, where c is fixed, of a free hyperplane arrangement are derivation radical.

Ambient- And High-Temperature Mechanical Properties Of Isochronally Aged Al–0.06sc, Al–0.06zr And Al–0.06sc–0.06zr (At.%) Alloys, Keith E. Knipling, David N. Seidman, David C. Dunand

U.S. Navy Research

Ambient- and high-temperature precipitation strengthening are investigated in Al–0.06Sc, Al–0.06Zr and Al–0.06Sc–0.06Zr (at.%) alloys. Following solidification, Sc is concentrated at the dendrite peripheries while Zr is segregated at the dendrite cores. During isochronal aging, precipitation of Al3Sc (L1₂) commences between 250 and 300 °C for Al–0.06Sc, and reaches a 429 MPa peak microhardness at 325 °C. For Al–0.06Zr, precipitation of Al3Zr (L1₂) first occurs between 400 and 425 °C and reaches a 295 MPa peak microhardness at 475 °C. A pronounced synergistic effect is observed when both Sc and Zr are present. Above 325 °C, Zr …

Bedside Method To Estimate Actual Body Weight In The Emergency Department, Robert G. Buckley, Christine R. Stehman, Frank L. Dos Santos, Robert H. Riggenburgh, Aaron Swenson, Nathan Mjos, Matt Brewer, Sheila Mulligan

U.S. Navy Research

Background:

Actual body weight (ABW) is important for accurate drug dosing in emergency settings. Oftentimes, patients are unable to stand to be weighed accurately or clearly state their most recent weight.

Objective:

Develop a bedside method to estimate ABW using simple anthropometric measurements.

Methods:

Prospective, blinded, cross-sectional convenience sampling of adult Emergency Department (ED) patients. A multiple linear regression equation from Derivation Phase (n = 208: 121 males, 87 females) found abdominal and thigh circumferences (AC and TC) had the best fit and an inter-rater correlation of 0.99 and 0.96, respectively: Male ABW (kg) = -47.8 + 0.78 * (AC) …

Investigation Of Electrical Transport In Hydrogenated Multiwalled Carbon Nanotubes, Adam L. Friedman, Hyunkyung Chun, Don Heiman, Yung Joon Jung, Latika Menon

U.S. Navy Research

Highly disordered multiwalled carbon nanotubes of large outer diameter (~60 nm) fabricated by means of chemical vapor deposition process inside porous alumina templates exhibit ferromagnetism when annealed in a H₂/Ar atmosphere. In the presence of an applied magnetic field, there is a transition from positive to negative magnetoresistance. The transition may be explained in terms of the Bright model for ordered and disordered carbon structures. Additionally, temperature dependent electrical transport experiments exhibit a zero-bias anomaly at low temperature.